Starship Asterisk*

Can a Neutron star form a normal star in time? I agree with Art. Give me one good reason why the neutron ball would turn into hydrogen. Even if that would be possible, radiation pressure would create an explosive expansion. Not to mention the violation of the law of conservation of energy, the main...

G'day astrolabe, There are two of what look like strong radio sources, one at 9:00 and, to the right of center, at about 4:00. They appear to be in the background and this (wull, yaahh) brings up a question. Definitely background. The red structure Andy Wade called a pompom, is merely the result of ...

The limit was computed by J. Robert Oppenheimer and George Michael Volkoff in 1939, using work of Richard Chace Tolman. Oppenheimer and Volkoff assumed that the neutrons in a neutron star formed a cold, degenerate Fermi gas. This leads to a limiting mass of approximately 0.7 solar masses. Modern es...

Orca wrote:The JPL site for New Horizons doesn't really discuss the propulsion system, by the way.

http://pluto.jhuapl.edu/common/content/ ... nGuide.pdf
Page 23, 2nd paragraph: Propulsion.

Cuold it be that as a BH evaporates energy the radiation draws heat with it and at the QM level the voids allow the cooler remaining mass to become ever denser in it's less-energetic state and the BH shrinks to a smaller diameter? Possible. The point is that the temperature of a black hole is more ...

I wonder how much mass moving it would take to change our orbit? Ahh, a chalenge! Using Earth units: Keplers third law says: 1 = a³/T² or T² = a³ when a is in Astronomical units and T is in years. The earth orbits in a circular orbit (almost), the circumference is 2πa, so the speed, v, is v = 2πa/T...

G'day folks, Never understood BH evaporation myself. If evaporation is basically matter changing state, and the gravity of a BH is strong enough to trap light, then how could matter either disappear (cease to be) or escape the gravity well??? Evaporation is more a semantical inaccuracy than a physic...

G'day Ed, Qev and Pete, Have we (the proverbial we) actually seen a black hole disappear? Never read about it. That would have been stunning news. BTW, i'm not an astronomer of profession, i'm JAA (Just An Amateur). Regarding the 'deficit' in black holes, well, one could expect more. Not all stars a...

G'day Ed, my capacity is to think on this scale is in simpler terms such that includes my wondering if black holes could eject matter??? [...] I cannot fathom matter "disappearing" into a hole without somewhere else to go. General relativity explains that mass deforms the spacetime fabric....

From inside, the event horizon might encompass an entire universe. What would that look like? In the late seventies and early eighties of last century there was a quest for the 'missing mass'. This was spawned by the idea that a black hole does not necessarily has to be small. So is it possible tha...

I dont get it why it has to be a poll. Join the club! Why would someone vote for number other than that (correct number)? There may be just one reason: it is a kind of intelligence test. Since the correct answer is not any of the items to choose, -only integers are listed, the answer is considerabl...

According to the article, PN's provide material back into the galactic medium... I am not the person to properly answer your question but it seems at least plausible that the PN remnants could wind up as part of a new planet. A planetary nebula itself will not end as a new proto planet. What you se...

G'day Apodimagers, Saw an impressive image at: http://www.galex.caltech.edu/media/glx2008-01r_img01.html Full resolution image can be found as: http://www.galex.caltech.edu/media/images/glx2008-01r_img01.tif Although M83 has performed 10 times as APOD, the recent composite image shows the combinatio...

Planetary Nebula is kind of a misnomer and has nothing to do with planets. Telescope in these past days were not half as good as moderate amateur telescopes nowadays. Most of all, in modern day telescopes a lot of effort is spent on the stability of the mounting and its foundation. Christiaan Huyge...

henk, how is the 'W' of VoorWerp pronounced? An Anglophone on BAUT suggest the whole word as "four-vairp". How close is that? J. Close, but no cigar. The W is comparable to What, Which, Where,(Wolverhampton) Wanderers. The F in "four" is to strong, more like the V in Victory, in...

Maybe this has already been asked, but why do we know that whatever is sublimating on Mars is water ice? Couldn't it also be solid CO2? (which on earth is also stark white) A thread on this topic was running, you might find more detailed answers and background information in that thread. As iamluck...

Thanks Art for your reply. A gravitational force of EXACTLY : - K * z defines an harmonic oscillator such that all the objects will have the same periodicity. (Note also that stars on the back & front sides of the bar will get a gravitational pull back to the center.) Right, if the distance betw...

http://antwrp.gsfc.nasa.gov/apod/ap080625.html The pronunciation of Hanny's Voorwerp in its original language is: HÄnneas VÓrwErp with Ä as in alms, art, calm Ó as in over, boat, no E as in ebb, set, merry I am now wondering if, in other countries, there is an equivalent to 1st April on the 25th of ...

From the text: ". . . the Milky Way . . . is not near any center ( expansion models do not allow for a discoverable center ) - a positional state that may not even be valid (one can however speculate about the spatial distribution of galaxies relative to the singularity which doesn't have a lo...

The cylinder (and z axis) can be thought of as rotating around the x axis with centrifugal force equal to K * z approximately balanced by the cylinder's gravitational force. The force (proportional to the distance from the center of the galaxy, attractive towards the center) explains why stars don'...

Yes, that's correct. Angular momentum has to be conserved, and it's a vector quantity... direction counts. There is a anecdote about a gyroscope and Jean Perrin. I read the story as a younster in a book by George Gamov. The nice illustration in Gamovs book lacks in the following quote. << Quote: An...

That was me, Henk, not qev. My excuses, NoelC, for that mix up. And thanks for informing me with the "How did you do that" info. I followed a very basic approach. 1) Read two images 2) Made a correlation of both images in the frequency domain, by fast fourier transforms of the two red col...

Does anyone know what the blurred object in the upper right-hand corner is? It could be "just" another galaxy, but it doesn't look like it would be one. On first sight, yes, galaxy, since it is not shaped as a point. On second thought, the shape is rather weird. It resembles a shoe, seen ...

neufer wrote: For d < |z| < L : F(z) ~ - K * z

G'day Art,

The z direction, is that perpendicular to the disk of the galaxy? Or is the z direction along the bar of the galaxy? Judging the choise of a cylinder it is more likely to model the bar itself.

Andy Wade wrote:OK, the two images are available for download here:

Thanks Andy, for providing shelter for my images. I must admit, the animated gif that qev shared with us, outclasses my efforts. I wonder, how did he do that?